112 THE COW IN HEALTH AND DISEASE 



stored. This holds as much as one quart in 

 some cows. 



The interior of the cow's udder is made up 

 of numerous lobes, united by cellular tissue 

 which is yellow in color. Each of these lobes 

 is further subdivided into lobules which are 

 composed of very small cavities known as 

 alveoli, acini or cells. The fat content of the 

 milk is derived from these small lobules. The 

 fluid part of the milk is secreted here and 

 passes through these small ducts to the lobes, 

 where it gains access to still larger ducts. 

 These common ducts from each lobe converge 

 toward the base of the teat and form a cavity, 

 known as the lactiferous sinuses; these com- 

 municate quite freely and form right at the 

 base of the teat. The whole number of them 

 is known as the galactophorous sinus and this 

 is where the milk is stored until milking time. 



The udder of the heifer is usually small and 

 firm, but, as parturition approaches, it be- 

 comes swollen and tender showing that there 

 are changes going on within it. At, or imme- 

 diately after calving, milk is formed in the 

 udder. 



There are two processes that contribute to 

 the formation of milk, as follows : The small 

 acini or alveoli, mentioned above, furnish the 

 fat content of the milk from the shedding of 

 cells lining these cavities, and the fluid por- 

 tion of the milk is formed from the lymph that 

 flows through the udder. If we examine one 



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